I've lived in the Antelope Valley for 14 years - here is some info:
Coyotes - you will see them periodically in the desert areas, but they stay away from inhabited areas for the most part
Mountain Lions & Racoons - I'm not aware of any local sightings of these types of animals
Rats - Mice -- whenever we have new building the local area does tend to see an increase in field mice - rats not so much.
Bears - we don't get those, but on the morning news today KTLA.com there was a bear in the neighborhood of La Crescenta, which will occur in the Acton, Leona Valley and other mountain areas.
We are a great community - rural without the animal issues. As to bugs, we have the normal mosquitoes and flies, but not much else. If you are looking to rent or buy in Palmdale, I'll be happy to help you with your search.
Tamara Stoebe, REALTOR, GRI, e-PRO, CHS, QSC
DRE License #01827461
Prudential Troth REALTORS
1801 W. Ave. K
Lancaster, CA 93534
Cell: (661) 466-6849
Fax: (661) 422-3006